* THE SOFTWARE.
*/
-#include <stdio.h>
-#include <stdlib.h>
+#include "fips.h"
+
+#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
+#include <sys/stat.h>
#include <sys/wait.h>
+#include <talloc.h>
+
+#include <linux/limits.h>
+
+#include <fcntl.h>
+#include <gelf.h>
+
+#include "execute.h"
+#include "xmalloc.h"
+
+/* Terminate a string representing a filename at the final '/' to
+ * eliminate the final filename component, (leaving only the directory
+ * portions of the original path).
+ *
+ * Notes: A path containing no '/' character will not be modified.
+ * A path consisting only of "/" will not be modified.
+ */
+static void
+chop_trailing_path_component (char *path)
+{
+ char *slash;
+
+ slash = strrchr (path, '/');
+
+ if (slash == NULL)
+ return;
+
+ if (slash == path)
+ return;
+
+ *slash = '\0';
+}
+
+/* Find the absolute path of the currently executing binary.
+ *
+ * Returns: a string talloc'ed to 'ctx'
+ */
+static char *
+get_bin_name (void *ctx)
+{
+ const char *link = "/proc/self/exe";
+ char *name;
+
+ /* Yes, PATH_MAX is cheesy. I would have preferred to have
+ * used lstat and read the resulting st_size, but everytime I
+ * did that with /proc/self/exe I got a value of 0, (whereas
+ * with a "real" symbolic link I make myself I get the length
+ * of the filename being linked to). Go figure. */
+ int name_len = PATH_MAX + 1;
+
+ name = talloc_size (ctx, name_len);
+ if (name == NULL) {
+ fprintf (stderr, "Out of memory.\n");
+ exit (1);
+ }
+
+ name_len = readlink (link, name, name_len - 1);
+ if (name_len < 0) {
+ fprintf (stderr, "fips: Error: Failed to readlink %s: %s\n", link,
+ strerror (errno));
+ exit (1);
+ }
+
+ name[name_len] = '\0';
+
+ return name;
+}
+
+/* Does path exist? */
static int
-fork_exec_and_wait (char * const argv[])
+exists (const char *path)
+{
+ struct stat st;
+ int err;
+
+ err = stat (path, &st);
+
+ /* Failed to stat. It either doesn't exist, or might as well not. */
+ if (err == -1)
+ return 0;
+
+ return 1;
+}
+
+/* Given a program name, search the PATH environment variable and
+ * return the first absolute path to 'program'.
+ *
+ * Returns: A string talloc'ed to 'ctx'.
+ *
+ * Note: This function aborts the current program if 'program' cannot
+ * be located by searching PATH.
+ */
+static char *
+search_path_for_program (void *ctx, const char *program)
{
- pid_t pid;
- int i, status;
+ char *orig_path, *path, *colon, *dir, *candidate;
+ void *local = talloc_new (ctx);
+
+ /* If the program name already contains a slash, then this is
+ * an absolute (or relative) path. Either way, we don't search
+ * PATH, since we can directly open this filename. */
+ if (strchr (program, '/'))
+ return talloc_strdup (ctx, program);
+
+ orig_path = path = getenv ("PATH");
+
+ while (*path) {
+ colon = strchr (path, ':');
+
+ if (colon) {
+ dir = talloc_strndup (local, path, colon - path);
+ path = colon + 1;
+ } else {
+ dir = path;
+ path = path + strlen (path);
+ }
- pid = fork ();
+ candidate = talloc_asprintf(local, "%s/%s", dir, program);
- /* Child */
- if (pid == 0) {
- execvp (argv[0], argv);
- fprintf (stderr, "Failed to execute:");
- for (i = 0; argv[i]; i++) {
- fprintf (stderr, " %s", argv[i]);
+ if (exists (candidate)) {
+ talloc_steal (ctx, candidate);
+ talloc_free (local);
+ return candidate;
+ } else {
+ talloc_free (candidate);
}
- fprintf (stderr, "\n");
+ }
+
+ fprintf (stderr, "Cannot find program %s (looked in %s)\n",
+ program, orig_path);
+ exit (1);
+}
+
+/* Is the given elf program 32 or 64 bit?
+ *
+ * Note: This function aborts the current program if 'program' cannot
+ * be opened as a valid ELF file. */
+static int
+elf_bits (const char *program)
+{
+ Elf *elf;
+ GElf_Ehdr ehdr;
+ int fd, class;
+ void *local = talloc_new (NULL);
+ char *absolute_program = search_path_for_program (local, program);
+
+ fd = open (absolute_program, O_RDONLY, 0);
+ if (fd < 0) {
+ fprintf (stderr, "fips: Failed to open %s: %s\n", absolute_program,
+ strerror (errno));
exit (1);
}
- /* Parent */
- waitpid (pid, &status, 0);
- if (WIFEXITED (status)) {
- return (WEXITSTATUS (status));
+ if (elf_version (EV_CURRENT ) == EV_NONE) {
+ fprintf (stderr, "fips: Failed to initialize elf library: %s\n",
+ elf_errmsg (-1));
+ exit (1);
}
- if (WIFSIGNALED (status)) {
- fprintf (stderr, "Child terminated by signal %d\n",
- WTERMSIG (status));
+
+ elf = elf_begin (fd, ELF_C_READ, NULL);
+ if (elf == NULL) {
+ fprintf (stderr, "fips: Call to elf_begin on %s failed: %s\n",
+ absolute_program, elf_errmsg(-1));
+ exit (1);
}
- return 1;
+
+ if (elf_kind (elf) != ELF_K_ELF) {
+ fprintf (stderr, "fips: Not an ELF object: %s\n", absolute_program);
+ exit (1);
+ }
+
+ if (gelf_getehdr (elf, &ehdr) == NULL) {
+ fprintf (stderr, "fips: getehdr on %s failed: %s\n",
+ absolute_program, elf_errmsg (-1));
+ exit (1);
+ }
+
+ class = gelf_getclass (elf);
+
+ if (class == ELFCLASSNONE) {
+ fprintf (stderr, "fips: getclass on %s failed: %s\n",
+ absolute_program, elf_errmsg (-1));
+ exit (1);
+ }
+
+ talloc_free (local);
+
+ if (class == ELFCLASS32)
+ return 32;
+ else
+ return 64;
+
+}
+
+/* Find the appropriate path to the libfips wrapper.
+ *
+ * This involves, first, examining the elf header of the 'program'
+ * binary to be executed to know whether we should look for
+ * libfips-32.so or libfips-64.so.
+ *
+ * Next, we find the absolute patch containing the library as follows:
+ *
+ * 1. Look in same directory as current executable image
+ *
+ * This is to support running from the source directory, without
+ * having installed anything.
+ *
+ * 2. Look in relative path from $(foo)/$(bindir) to
+ * $(foo)/$(libdir)/fips based on $(foo) from current executable
+ * image and configured $(bindir) and $(libdir).
+ *
+ * We do this rather than looking directly at the configured
+ * $(libdir) to support cases where the application may have been
+ * moved after being installed, (in particular, we want to be
+ * particularly careful not to mix one program with a different
+ * wrapper---so this "nearest search" should most often be
+ * correct.
+ *
+ * Returns: a string talloc'ed to 'ctx'
+ */
+static char *
+find_libfips_path (void *ctx, const char *program)
+{
+ char *bin_path, *library, *lib_path;
+ int bits;
+
+ bits = elf_bits (program);
+
+ library = talloc_asprintf(ctx, "libfips-%d.so", bits);
+
+ bin_path = get_bin_name (ctx);
+
+ chop_trailing_path_component (bin_path);
+
+ lib_path = talloc_asprintf(ctx, "%s/%s", bin_path, library);
+
+ if (exists (lib_path))
+ return lib_path;
+
+ talloc_free (lib_path);
+
+ lib_path = talloc_asprintf(ctx, "%s/" BINDIR_TO_LIBFIPSDIR "/%s",
+ bin_path, library);
+
+ if (exists (lib_path))
+ return lib_path;
+
+ fprintf (stderr, "Error: Failed to find library %s.\n", library);
+ fprintf (stderr, "Looked in both:\n"
+ "\t%s\n"
+ "and\n"
+ "\t%s/" BINDIR_TO_LIBFIPSDIR "\n", bin_path, bin_path);
+
+ fprintf(stderr, "\nIt's possible fips was not compiled with support for %d-bit applications.\n", bits);
+ fprintf(stderr, "Perhaps you need to install gcc-multilib and re-compile fips?\n");
+ exit (1);
}
int
-execute (int argc, char * const argv[])
+execute_with_fips_preload (int argc, char * const argv[])
{
+ void *ctx = talloc_new (NULL);
+ char *lib_path;
+ char *ld_preload_value;
char **execvp_args;
int i;
- execvp_args = malloc((argc + 1) * sizeof(char *));
- if (execvp_args == NULL) {
- fprintf (stderr, "Out of memory,\n");
- return 1;
- }
+ execvp_args = xmalloc((argc + 1) * sizeof(char *));
for (i = 0; i < argc; i++) {
execvp_args[i] = argv[i];
/* execvp needs final NULL */
execvp_args[i] = NULL;
- return fork_exec_and_wait (execvp_args);
+ lib_path = find_libfips_path (ctx, argv[0]);
+
+ ld_preload_value = getenv ("LD_PRELOAD");
+
+ if (ld_preload_value) {
+ ld_preload_value = talloc_asprintf(ctx, "%s:%s",
+ ld_preload_value,
+ lib_path);
+ } else {
+ ld_preload_value = lib_path;
+ }
+
+ setenv ("LD_PRELOAD", ld_preload_value, 1);
+
+ talloc_free (ctx);
+
+ execvp (argv[0], argv);
+ fprintf (stderr, "Failed to execute:");
+ for (i = 0; argv[i]; i++) {
+ fprintf (stderr, " %s", argv[i]);
+ }
+ fprintf (stderr, "\n");
+ exit (1);
}
projects / fips / blobdiff